Month: April 2023

Rooftop Rainwater harvesting – Process and Maintenance

An easy step-by-step guide to install rooftop rainwater harvesting (RRWH) at your location.

  • Solution for government buildings, commercial buildings, factories, housing societies, educational institutions, individual houses, etc.

Water scarcity, pollution in water bodies, access to clean drinking water, threat to water-dependent ecology, erratic rainfall and climate change are pressing issues around water management. Several government schemes and policies, non-governmental organisations, and private companies work to address these water issues.

Rainwater harvesting is the technique of collection, filtration and storage of rainwater at surface or in subsurface aquifers, before it is lost as surface run-off, such that the collected water can be harvested in the time of need.

You as individual citizens, colony members, school representatives can harvest rainwater falling in your premises.

will bring the major benefits of:

(i) Maintain level of groundwater in borewell, and prevent the threat of borewell drying up  which otherwise leads to drilling another borewell

(ii) Maintain or reduce TDS level of water and reduce your water purification needs, especially RO treatment which is installed in most urban households. RO creates a lot of reject water in its process, RWH will reduce dependency on RO treatment.

You also contribute to water conservation.

In this article you can find useful resources to install a roof rainwater harvesting system at your place.

Where to install rooftop rainwater harvesting system?

RRWHS can be installed in any building having a roof area, and space to store rainwater in a tank or recharge your own borewell as groundwater. Government offices, institutions, industries, apartments buildings, bungalows, etc., can install rainwater harvesting systems. Schools can also be a  great setting for installing rainwater harvesting systems, as it will meet water needs for students’ and staff, and also inculcate practical learning about water conservation and environment among students.

Types of rainwater harvesting:


One way of harvesting rainwater is to store it in a tank on the ground, after filtering it. Depending on water usage and rainfall availability, a large portion of a year’s water needs can be met by this stored rainwater.


Often, space to make storage tanks for rainwater, is inadequate, and in such cases it can be used to recharge the groundwater.In most cases, a functioning borewell itself can be recharged with rainwater after filtering. In some other cases, a defunct borewell (functioning earlier but now not functional), can be used for recharge. If there is no current borewell, a recharge borewell can be made, after studying the aquifer/groundwater characteristics of the location.


RRWHS is often implemented as a combination of storage and recharge. The rainwater, after filtering, is led to an existing storage tank on surface. Overflow from the tank, not uncommon in monsoon, is led to recharge the borewell.

Each Components of a rooftop rainwater harvesting system is explained below:

  1. Roof: The roof of any building is an important catchment area, which is a surface on which rainwater falls and it can be directed to storage or for shallow aquifer recharge. The roof can be sloping or flat, and it is important to check that the finishing materials or paint used on the roof is non-toxic and does not contain mercury. Before the first rains, it is important to clean the roof thoroughly to avoid dirt and other impurities from mixing with rainwater.


  1. Pipes: Rainwater can be brought down from the roof through pipes. The size of pipes can be decided as per rainfall intensity and roof area. For aesthetic purposes, sometimes people use rain chains instead of pipes. These chains direct the water flow from roof to floor, reduce splashing and create a good visual as water flowers down.


  1. First flash valve: The first rain of the monsoon season is not stored because the dirt and organic matter mixes with water and such water can create contamination in storage tank. So the first flash valve removes this water, and subsequent rainwater can be collected.


  1. Filter system: A filter is needed to prevent stones, leaves, dust and other particles from entering storage tanks or recharge pits. It can be done using NeeRain rooftop rainwater filters to be mounted a few feet above ground on the pipeline bringing water from the roof.


  1. Storage: The capacity of a storage tank can be designed based on space availability, needs and usage. If the water is to be used for drinking purposes, the tank can be smaller than if the intended use is for non-drinking purposes.
  2. Recharge and excess outlet: Once the storage tank is filled, the overflow can be directed to recharge groundwater.
  •  Maintenance
    1. Check the terrace areas for any major spillage of oil, chemicals or garbage and clean it particularly at the beginning of the monsoon season and then every few months.
    2. Water from initial two rain should be drained off. Then close the flash valve for subsequent rains, so the water flows from roof through the filter to the tank or recharge as per design.
    3. If rainwater is being stored and used, then regular water quality tests will have to be done to ensure drinking water standards, and perform treatment if necessary.
    4. Storage tank should be cleaned once a year especially before the monsoon season.
    5. Stored rainwater can be disinfected by UV or boiling water before use.


Neerain is proud to republish this article for spreading awareness about situation of water, for our stakeholders. Credit whatsoever goes to the Author.

This article is published by: –

Rooftop Rainwater harvesting (RRWH)

We would like to spread this for the benefit of fellow Indians.


Publish On: Jun 26 , 2021.





Rooftop rainwater harvesting: A tool for refashioning India’s water management practice

India’s rapid urban growth is putting pressure on its already crumbling base of public service arrangements — especially its management of water and sanitation services, whose safe and reliable availability proved to be the first line of defense against the scourges of the novel coronavirus disease (COVID-19). It holds potential to support the country’s preparedness against the incipient challenges of changing climate.

An appalling confusion grips our policymakers and planners. While the supply-demand gap is expected to widen by 50 percent by 2030, many are still left without access to safe and sustainable water and sanitation services.

At least five Indian cities are already reported to have joined the list of world’s 20 largest water-stressed cities. A case in point is the metropolitan regions of Bangalore and Chennai, which source their waters from a distance of 95 kilometres and 200 km, respectively.

This organisation of infrastructural arrangement not only puts a heavy burden on the states’ exchequers by demanding exorbitant amounts of funds for their design, installation, and operation but also languishes the residents of these cities dependent on a single source of water for a bulk of their daily demands to the whims of inter-regional conflicts over water sharing as well climate-related shocks.

If we look at the present portfolio of water resources management for other cities, it will not be wrong to claim that many more will soon become qualified for joining this infamous list.

Exploring the complex problems

Water availability in India remains on the mercy of erratic patterns of precipitation. The southwest monsoon alone accounts for 70-75 per cent of the total precipitation falling in India, especially in regions along the west coast, the north-eastern states, West Bengal and Odisha, which are characterised by patterns of heavy rainfall events within limited time duration.

Photo courtesy: The economic time

It is estimated that India receives its total precipitation within a limited time duration of 100 hours out of 8,760 annual hours in total.

With temperatures postulated to rise owing to changing climate, precipitation patterns can only be expected to become more capricious in their operation. Nowhere will these uncertainties and incidental challenges be more pronounced than in our burgeoning towns and cities, which are already facing water shortages during the summer months and at time, experiencing floods during monsoon.

A World Bank (2018) study expounded that by 2050, annual average precipitation will increase to 1-20C under climate-sensitive scenario and 1.5-30C under carbon-intensive scenario.

Such changes are expected to increase precipitation, which will come in the form of reduced rainy days but more days of extreme precipitation events.

Combined with this peculiarity in the evolving unpredictability of precipitation patterns over the Indian subcontinent, the way Indian cities have sprung and continues to develop also pose a risk to their future sustainability.

The concretisation of urban landscapes, symbolic of modern town planning imaginaries as to what an exercise in urban development should produce, is found to be increasing flood peaks from 1.8-8 times and volume of flood by up to six times.

Storm water drainage systems, installed to allay the threats of urban deluge, are still designed for rainfall intensity of 20-25 millimetre per hour duration. It is, therefore, not unnatural that the carrying capacities of these drains easily get overwhelmed during the incidences of heavy precipitation.

Illegal encroachment along storm water drains and urban rivers also aggravates the situation, not least by opening up spaces of active political contestation and negotiations.

A paradigm shift needed

As an extension of India’s colonial history, management of water, not unlike other key services, was bundled as part of the prerogative claims of post-independent public institutions with public participation programs designed later on to serve only a placatory function.

While this lead to systematic exclusion of public’s opinions in informing the design and implementation protocols of large public schemes, water management had, as a discipline, become a constituency-building tool. It allowed public authorities to appropriate the commissioning and management of large-scale and costly engineering arrangements to maximise control and legitimacy of their rule over its subjects.

Guided by the underpinnings of this hydraulic paradigm, an inevitable boost in the development of behemoth engineering projects was witnessed in the 20th century. It took the form of multi-purpose dams, irrigation canals, public water distribution systems, etc.

Despite such an extended spree of building large dams and infrastructures, India has now become a ‘water-stressed’ country, with only about 6-8 percent of installed water storage capacity, growing incidences of water pollution, falling freshwater biodiversity and prevailing inequities in water supply and sanitation services distribution.

To make matters worse for the proponents of supply-side management approach, their arguments lobbying for continuing with this strategy are quickly losing credence in the wake of growing concerns over environmental degradation, involuntary displacement of local population, stringent land acquisition policies, complexity of transboundary negotiations for risks and benefits sharing, and huge cost escalation and time lags that are characteristic of these projects.

Rising national empathy for river rejuvenation, watershed conservation and active public participation has, on the other hand, already started scripting a new paradigm for India’s water management. It prompts decision-makers to look for solutions in the collective efforts of the citizens in managing their issues locally.

But is this really a new paradigm for us? Does the annals of Indian history provides another form of legacy that somehow can provide a moral thrust to this growing momentum?

Yes, indeed. Our Vedic ancestors, in their appreciation of the timeless bounty of water, always offered timely obeisance to water’s eternal gifts to mankind. Their reverence to water can be found in the hymns and prayers offered to Varuna and Indra — Vedic Gods associated with water —  to riveting architectural gems and literary delights, each underscoring the centrality of water in our cultural revelries.

However, with the advent of modernist’s ideology of taming the nature, we did lend ourselves in to following an exploitative relationship with nature, weaning away from a reverential one which our ancestors had so meticulously developed over the course of history.

It is time our policies are re-designed to reflect these values.

Rooftop rainwater harvesting: A simple tool to empower people

Rooftop rainwater structures are perfectly poised to engender a transformative wave of public engagement in water management, thus, as a corollary, making water management an exercise in nurturing democratic routines.

To ensure that public enthusiastically purchases this concept, a country-wide behavior change campaign can be launched along the lines of Swachh Bharat Mission that can improve people’s ‘ability’ and ‘motivation’ to romantically welcome these structures in their private premises.

It is generally observed that the actual design, construction and maintenance of these structures are left with the individual households and local masons with little or no regulation and monitoring from the concerned urban local bodies.

This does not bode well for the quality and performance of these structures. Local authorities should, therefore, accord explicit attention to the designing and management criteria in their respective byelaws and work to strengthen the enforcement thereof.

Local non-profits and private stakeholders can be roped in to build area specific water conservation plans in partnership with local residents outlining what can work and what cannot according to the area based hydrogeological and prevailing social conditions.

There are several people who have been fervently advocating for the cause of water harvesting. They should be supported to build an arsenal of local champions who can then effectively mobilise the mood of communities in and around their regions for installing rooftop rainwater harvesting systems.

They will be a key to promote a ‘do-it-yourself’ model of engagement.

The discipline of water management is now situated at the precipice of change; it has opened its traditionally closed and ‘elite’ routines to the democratic practices of dialogue, inclusion and transparency.

Adoption of rooftop rainwater harvesting practice provides just the right opportunity for our water managers to leverage this wave of change that is effectively about breaking the boundaries between experts and non-experts.

Neerain is proud to republish this article for spreading awareness about situation of water, for our stakeholders. Credit whatsoever goes to the Author.

This article is published by: –

We would like to spread this for the benefit of fellow Indians.

Author: Jaidev Joshi

Publish On: July 02 2021


It’s a 15% water cut, but many areas in Mumbai dryor down to a trickle

MUMBAI: Citizens from several areas in Mumbai have been complaining about the lack of water supply in their localities. Some have even said that they have not been receiving water at all or are getting only a trickle, and are having to depend on water tankers and bottled water for drinking.

Starting from March 31 onwards, the BMC had announced a 15%water cut all across Mumbai for the next 30 days. This was due to the tunnel carrying water to Mumbai getting damaged in Thane. The tunnel was damaging during the digging of a borewell subsequently causing a massive leakage. Again last week, the city’s water main was damaged at Kopri in Thane aggravating the situation. The BMC is estimated to spend Rs 13 crore for the repairs, which it said it would recover from the builder whose workers damaged the tunnel in Wagale Estate.

Renu Kapoor, a Colaba resident said that there has not been a drop of water in their society leaving them with no option but depend on water tankers. “Our supply hours are in the evenings daily and since the last two days we have not been getting any water. The situation has completely caught us unaware and we are resorting to using bottled water for drinking purposes,” said Kapoor.

Photo courtesy: Salahuddin

Ajay Multani, another Colaba resident said that initially as there was reserve water in their tank they could manage, however, when water did not come for the second day the situation got worse. “On Sunday, also we got water for hardly ten minutes. The problem is across all buildings in Colaba,” said Multani.

Former Bandra corporator Asif Zakaria said that the problem was in their locality too. “While a 15% cut has been officially announced but its way beyond it with over 50% reduction in water supply. Fague ends are getting nowhere at all and the water tankers that the BMC is providing is clearly insufficient,” said Zakaria.

Photo courtesy: Hindustan Time

Residents in areas like Gowalia Tank area also complained off no water supply. “We visited the hydraulic department of the BMC however they could not commit till when the issue would be resolved,” said a resident.

When contacted, additional municipal commissioner P Velrasu said on Monday a meeting was conducted to assess the situation. “There were some augmentation measures done. The issue should settle down Tuesday night and Wednesday,” he said.

Neerain is proud to republish this article for spreading awareness about situation of water, for our stakeholders. Credit whatsoever goes to the Author.

This article is published by: –

We would like to spread this for the benefit of fellow Indians.

Author: Richa Pinto

Publish On: April 04, 2023.


We look forward to the participation of multiple delegates from G20 countries, along with representatives of international organizations, deliberating on the global best practices and ideas on water resource management

India assumed the G20 Presidency on December 1st, 2022, taking over from Indonesia. The G20 leadership offers the country the opportunity to showcase the “India story” to the world countering multiple contingencies including global warming, food and energy shortage, terrorism, geopolitical conflict, and bridging the digital divide.

As the largest democracy in the world, and the fastest growing economy, India’s G20 presidency will play a crucial role in building upon the significant achievements of the previous 17 presidencies. The G20 theme of this year “One Earth, One Family, One Future” perfectly captures India’s underlying philosophy of “Vasudhaiva Kutumbakam” (the world is one family), which will guide India’s G20 leadership.

The first G20 Environment and Climate Sustainability Working Group (ECSWG) meeting concluded with a positive note with all G20 countries expressing support on the themes outlined by MoEF&CC for India’s Presidency. Discussions on restoring degraded land, promoting blue economy along the coastal sustainability, enhancing biodiversity, preventing forest fire and marine littering and strengthening Circular Economy have created the platform for a more insightful deliberation in the second Summit.

Best Practices on Water Resource Management

During its G20 Presidency stint, India is looking forward to an integrated, comprehensive and consensus-driven approach to mitigate the challenges of climate change and water scarcity. Water conservation in fact is an integral part of the Indian identity and cultural history and has become even more relevant in the present day.  “Saving” water is not just about conservation, but to ensure the availability of enough clean water at any given time and place to meet our combined needs.

The Ministry of Jal Shakti, Government of India has taken various initiatives for promoting water conservation through Artificial Recharge and Rain Water Harvesting. The Jal Jeevan Mission program aims to connect more than 193 million rural households with functional household tap water connections by 2024. Our ambitious Namami Gange mission has created a paradigm shift in river rejuvenation, pollution abatement, conservation of ecosystems and holistic approach to river basin management. It has recently been recognized as one of the top 10 World restoration flagships to revive the natural world by UN.

India is also implementing the largest dam rehabilitation program in the world, to build climate resilience for critical water storage infrastructure.


Further, to ensure long-term sustainability of groundwater resources through a combination of demand and supply side interventions, the scheme of Atal Bhujal Yojana is being implemented through community led, Gram Panchayat-wise Water Security Plans having convergence with ongoing /new schemes.

With these efforts and many more schemes, India is gradually moving towards the goal of becoming a water secure nation by year 2047. In this scenario, we are eager to host the second G20 Environment and Climate Sustainability Working Group (ECSWG) meeting focusing on water conservation and managing water resources sustainably and equitably.


We look forward to the participation of multiple delegates from G20 countries, along with representatives of international organizations, deliberating on the global best practices and ideas on water resource management. I am confident that discussions on river rejuvenation, focusing on the National Mission for Clean Ganga, Climate Resilient infrastructure, Ground Water Management, Strategies for universal access to sanitation and clean drinking water, through the Swachh Bharat Mission and Jal Jeevan Mission will help participating countries to learn from each other and accelerate achievement of the sustainable development goals.


History and heritage are synonymous to Gujarat. Glorious Gujarat is home to many ancient city ruins, palaces, forts and tomb standing proudly bearing testimonies to the golden era of dynasties. The stepwell of Rani ki Vav and Adalaj Vav demonstrate the ancient water management practices of India’s long-standing tradition of conserving water resources. Gujarat with its mix of the old and the new-traditional water wisdom and modern technologies used in creating water infrastructure, will provide a valuable platform for 20 countries to bring out and learn from the best in each.


Neerain is proud to republish this article for spreading awareness about situation of water, for our stakeholders. Credit whatsoever goes to the Author.


This article is published by: –

G20: Water Conservation for a more Sustainable Climate

We would like to spread this for the benefit of fellow Indians.


Publish On: March 30, 2023.

Rain Water Harvesting

With the human population facing major water scarcity and reports suggesting that more than half the world’s population will be living in water-stressed regions by 2050 (Water Aid), there is an urgent need for a system that helps the human race get access to fresh water. The solution to this problem is rainwater harvesting. It is the most sustainable way of accessing fresh water and does not require any energy for functioning. It does not deplete any natural resources, on the contrary, helps conserve and protect the natural habitat. This read is all about understanding the steps of rainwater harvesting and understanding how there is a need for rainwater harvesting.

Types of rainwater harvesting:

The types of rainwater harvesting will help us understand the system better. It is best to learn about them so we know which one works best for us and accordingly learn about the steps of rainwater harvesting.

1)            Surface rainwater harvesting

2)            Rooftop Rain Water

1)            Surface rainwater harvesting

In urban areas, rainwater flows away as surface runoff. This runoff can be caught and used for recharging aquifers by adopting appropriate methods.


2)            Roof Top Rain Water Harvesting

Rooftop Rain Water Harvesting is the technique through which rainwater is captured from the roof catchments and stored in reservoirs. Harvested rainwater can be stored in sub-surface ground water reservoir by adopting artificial recharge techniques to meet the household needs through storage in tanks.

The Main Objective of rooftop rainwater harvesting is to make water available for future use. Capturing and storing rainwater for use is particularly important in dryland, hilly, urban and coastal areas. In alluvial areas energy saving for 1mt rise in groundwater level is around 0.40 kilo watt per hour.

Need for Rooftop Rain Water Harvesting

  1. To meet the ever-increasing demand for water
  2. To reduce the runoff which chokes storm drains
  3. To avoid flooding of roads
  4. To augment the groundwater storage and control decline of water levels
  5. To reduce groundwater pollution
  6. To improve the quality of groundwater
  7. To reduce soil erosion
  8. To supplement domestic water requirement during summer, drought etc.

Advantages of Rain Water Harvesting

  1. Provides self-sufficiency to your water supply
  2. Reduces the cost for pumping of groundwater
  3. Provides high-quality water, soft and low in minerals
  4. Improves the quality of groundwater through dilution when recharged to groundwater
  5. Reduces soil erosion in urban areas
  6. The rooftop rainwater harvesting is less expensive
  7. Rainwater harvesting systems are simple which can be adopted by individuals
  8. Rooftop rain water harvesting systems are easy to construct, operate and maintain
  9. In hilly terrains, rooftop rainwater harvesting is preferred
  10. In saline or coastal areas, rainwater provides good quality water and when recharged to groundwater, it reduces salinity and also helps in maintaining balance between the fresh-saline water interface
  11. In Islands, due to limited extent of freshwater aquifers, rainwater harvesting is the most preferred source of water for domestic use
  12. In deserts, where rainfall is low, rainwater harvesting has been providing relief to people

Safety Consideration

1)   Storage in Ground Water Reservoir

a) For rooftop rainwater harvesting through existing tubewells and handpumps, filter or desilting pit should be provided so that the wells are not silted.

b) Such tubewells if pumped intermittently, increase the efficiency of recharge.

c) If the groundwater reservoir is recharged through, shaft, dug well etc., inverted filter may be provided.

2)   Storage in Tanks

a) A storage tank should not be located close to a source of contamination, such as a septic tank etc.

b) A storage tank must be located on a lower level than the roof to ensure that it fills completely.

c) A rainwater system must include installation of an overflow pipe which empties into a non-flooding area. Excess water may also be used for recharging the aquifer through dug well or abandoned handpump or tubewell etc.

d) A speed breaker plate must be provided below inlet pipe in the filter so as not to disturb the filtering material.

e) Storage tanks should be accessible for cleaning.

f) The inlet into the Storage tank should be screened in such way that these can be cleaned regularly.

g) Water may be disinfected regularly before using for drinking purpose by chlorination, treating with UV light or boiling etc.

How Much You Can Collect and  Collection Efficiency

How efficiently the rainfall can be collected depends on several considerations. Collection efficiencies of 90% are often used depending on the specific design.

Rainfall Reliability.

The first step is to determine how much water would be generated from your roof area. Average monsoon rainfall is used for this purpose.


Total quantity of water to be collected (cu.m.) = Roof Top Area (Sq.m.) x Average Monsoon Rainfall (m) x 0.9

For Example:

Area of your roof is 150 and average rainfall is 782 so rainwater that would be generated from your roof will be :

150 (Sq. mtr) X 782 (mm) X 0.9 (Co- efficient)

Every year 1,06,000 Liters will be filtered and harvested in your resource.

Neerain rooftop rainwater filter has won CII’s national Award for Excellence in water management 2022 for the innovative water saving product category on 29 Sep 2022.

NeeRain is featured on Doordarshan DD India, DD News and DD Girnar for common man centric work. NeeRain is inducted on board by Ministry of Housing and Urban Development (GOI) under Amrut 2.0 water innovation initiative.